fairchild



June 1-2, 1928. 1,673,353

' w. L. FAIRCHXLD METHOD OF VULCANIZING HOLLOW RUBBER ARTICLES Filed April 24, 1925 3 Sheets-Sheet l INVENTOR WALTER Z. BURCH/40 June 12. 1928.

W. L. FAIRCHILD METHOD 0F VULCANIZING HOLLOW RUBBER ARTICLES Filed April 24, 1926 3 Sheets-Sheet 2 June 12, 1928. 1,673,353

W. L. FAIRCHILD METHOD OF VULCANIZING HOLLOW RUBBER ARTICLES INVENTOR M4475? Lfir/mmp I E 513' J- :1

Patented June 12, 1928.

UNITED STATES WALTER L. FAIRCHILD, OF NEW YORK, N. Y.

METHOD OF VULOANIZING HOLLOW RUBBER ARTICLES.

Application filed April 24, 1926.

This invention relates to a new and improved method for vulcanizing hollow articles made of rubber, more particularly pneumatic tubes for vehicle tires.

This application isa continuation in part of my co-pending application, Serial No. H510 tiled December 11, 1925.

One of the objects of the invention is to provide a method of the above character, wherein live steam is utilized as a vulcanizing medium within the tube or other hollow article being subjected to the vulcanizing treatment, such that all portions of the ar ticle being subjected to said vulcanizing process will be uniformly treated, thereby producing a vulcanized article of uniform texture.

Another object of the invention is to provide a method of the above character for vulcanizing pneumatic tubes or other hollow articles formed of raw rubber com pound, utilizing live steam as a vulcanizing medium within the hollow article, wherein water of condensation is not permitted to collect in any regional part of the article being subjected to the vulcanizing process, and prevent that surface within said article covered by the water of condensation from receiving the same vulcanizing treatment as other portions thereof remaining out of contact with said water of condensation.

More particularly, my invention contemplates the provision of a method of the above character, wherein the article being subjected to the vulcanizing treatment is maintained in constant motion during the vulcanizing operation, whereby water of condensation from the live steam utilized as the "ulcanizing medium is not permit-ted to collect in any one part within the article being treated while the latteris being subjected to the vulcanizing operation.

Other objects and aims of the invention more or less specific than those referred to above, will be in part obvious and in part pointed out in the course of the following description of the steps and the relation of each step to one or more of the others thereof employed in carrying out my method, and the scope of protection contemplated will be indicated in the appended claims.

In the accompanying drawings, wherein I have illustrated preferred forms of appara- Serial No. 104,423.

tus for carrying out the various steps of my method,

Figure 1 is a view partly in elevation and partly in section, showing a preferred form of apparatus for carrying out the various steps of my method.

Figure 2 is a view similar to Figure 1 partly broken away, however, showing the parts in a diflerent position;

Figure 3 is an elevational view of my improved apparatus showing the manner in which several vulcanizing units may be driven from a single operating shaft;

Figure 4 is a detail view taken through part of the mechanism employed for controlling the supply of gases to the article to be vulcanized Figure 5 is a View similar to Figure 4, but showing the parts in a different position;

Figure 6 is a view partly in side elevation and partly in verti cal section, showing a differ'ent embodiment of my invention; and

Figure? is a rear elevat-ional view, partly broken away, of the embodiment of my in vention shown in Figure 6.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Before proceeding to describe in detail the construction of the apparatus adapted to carry out the various steps ofthe method constituting my present invention, it may here be noted that in the vulcanizing of pneu matic tubes and the like in individual molds wherein a gas such as steam has been utilized within the article to be vulcanized as a vulcanizing medium and also as a medium to maintain the article expanded within the mold,'ditticultyhas been experienced in obtaining a uniformly vulcanized article by reason of the fact that water of condensation collecting in the lowermost portion of said article being vulcanized has a tendency to obstruct or interfere with the vulcanizing operation upon that part of the article covered by said water of condensation, the

result being that the wall of the article is not uniformly vulcanized,-that is to say, uniform vulcanization of the entire wall of a pneumatic tube or a similar article cannot be had while water of condensation is allowed to collect and lie in a regional part of the article being vulcanized. I have, therehaust pipe 19.

fore, provided an apparatus whereby the article to be vulcanized is kept in constant motion so that water of condensation is not allowed to collect or remain stationary with in the article being vulcanized with. the resultant effect of a uniformly vulcanized article.

Proceedingynow to a description of the preferred form of mechanism employed for carrying out by improved method, the reference numeral 1 denotes the standard or support of the mold, the said standard at its upper end being provided with spaced arms 2 and 3, in which are journaled the pintles 4i and 5 respectively of the mold. The mold, which is denoted generally by the reference letter A, (Fig. 3) consists of two circular. sections .6 and 7, the lower mold section 6 havinga laterally extending arm 8, towhich ,is pivoted at 9, an arm 10 of the upper section 7, the construction being such that said upper section 7 may be swung upwardly and rearwardly with respect to the lowersection 6. The pintles 1 and 5 which are supportedin the. arms 2 and 3 of the standard 1 extend laterally in an in wardly direction from the lower section 6 of the mold, the construction being such that the mold as a unit may be rocked upon its horizontal axis in the bearings formed in the arms 2 and 8 of the standard 1.

The lower section 6 oft-he mold is pro vided with avulcanizing channel 11 pref erably of semi-oval cross sectional form,-and the upper section is likewise provided with a vulcanizing channel 12 preferably semicircular in cross section; the contour of said channels being such that whenthe mold sections are disposed in mating relation as shown in Figure 1 of the drawings, a vuL canizing chamber 13 will be formed of sub stantially elliptical cross section.

The meeting faces 14 and 15 of the mold sections are, of course, ground to a nicety, so that when the upper section is positioned upon its mating lower section a substantially perfect union will be formed between the mating edges of the vulcanizing surfaces of the respective mold sections.

The mold sections are adapted to be independently heated, preferably steam heated, a circular steam chamber 16 surrounding the vulcanizing channel of the lower mold and a circular steam chamber 17 surrounding the vulcanizing chamber. of the upper mold. Leading into the steam chamber 16 of the lower mold section is an intake pipe 18,

and leading therefrom at the diametrically opposite side of the mold section. is the en- The steam chamber of the upper mold section 7 is provided with an intake pipe 20 and the exhaust pipe 21; the disposition of theexhaust nipes 19 and 21 being suchthat when the mold as a unit is tilted to its rear-most position, as will be tember 2, 1925.

hereinafter described, any water of condensation which may be present in the steam chambers 16 and 17 will be discharged therefrom.

While the means for supplying the heating medium to the mold sections, are not shown in the present drawings, it will be understood that they will be connected with a suitable source of live steam supply, it being the intention to at all times supply such quantity oflive steamto said mold sec tions as will maintain them at a predetermined temperature, that is to say, at such a temperature aswill effect a vulcanizing operation on the rubber compound of which the article to be vulcanized is composed.

Located in the vulcanizing chamber formed by thechannels 11 and 12 of the re spective mold sections, is a tube 22 preferably formed of a raw rubber compound, saidtube being shown expanded into engage ment with the vulcanizing surface of the vulcanizing chamber ready to be subjected to the vulcanizing operation.

The mold sections when disposed in mating relation are adapted to be locked together, whereby a complete closure of the vulcanizing chamber is established during the vulcanizing operation, the locking means being sul'licient to hold said mating sections in engagement against the internal pressure exerted upon the tube being vulcanized. This locking means is not shown in the present drawings. I have preferably employed a locking means, such as is disclosed in my United States Patent No. 1,606,352, dated November 9, 1926, although, of course, any approved means may be employed for loclring the mold sections together, without departing from the spirit of the present invention.

In order to facilitate the production of a substantially. perfectl closure between the mold sections, and to hold the registering vulcanizing surfaces of the upper and lower mold sections in perfect registry, I preferably form upon the lower section a pair of circular bosses 23 which lit to a nicely within the correspondingly shaped recesses 24 formed in the upper mold section.

The tube 22 which is tov be subjected to the vulcanizing operation has been equip with a valve stem before its introduction into the mold, said valve stem, indicated at 25, extending laterally and inwardly through the wall of the lower mold section as clearly indicated in Figures 1 and 6. Suitable means, not shown, are provided for effecting a tight closure for this valve stem through the wall of the lower mold section; a meansparticularly well adapted to attain this object being shown in my pending application Serial Number 541,054, filed Sep Leading from a three-way valve 26 to the valve stem 25 is a flexible loo llill conduit 27, sufficient slack being provided in said flexible conduit to permit the mold unit to be rocked upon its pivotal support as will hereinafter be described.

The reference numeral 28 denotes a pipe adapted to conduct through the three-way valve 26 to the conduit 2?, the vuleanizing medium which, in the present; instance, is steam under suitable pressure, to maintain a tQlIlPQlElttllQ within the tube to be vulcanized substantially equal to the temperature at which the mold sections are maintained during the vulcanizing operation. The live steam is delivered to the pipe 2b from any suitable source of supply (not shown). Leading from the three-way valve is a pipe 29 which leads to the casing 30 of the three-way valve 31. The casing 30 is adapted to be connected with a source olf suction or vacuum, as by means of the pipe 32 and also with a source of tluid pressure, such for instance, as air or other gas, for a purpose hereinafter to be described.

Extending laterally inwardly from the lower mold section 6 is an arm 23 provided with a laterally extending pin or roller 34 which is adapted to be received in a slot 35 provided in the upper end of a rod 36 extending from'the housing 37 of the eccenlric 38 which is carried on a shaft 31) journaled in a bracket 40 clamped to the standard 1. 'The shaft 39 is adapted to be constantly driven. the construction being such that when the pin 3 t received in the slot or recess 35 of the rod 3th the eccentric 38 will, through said rod So and the arm 23 cause a rocking movement of the mold assembly upon its pivotal support.

pivotally mounted at -l-l upon a boss l2 depending from the lower section 6 of the mold, is a rod 43, the lower end of which is provided with a longitudinally extent'ling slot 44, the said slotted end portion of the rod t3 being provided with a laterally extending recess if), and extending into said slot is a pin 4C6 provided with a roller -l-T. The rod a3 is held normally in the position shown in Figure l of the drawings. as by means of the retractile spring L1H, so that during the rocking movement of the mold as above described, the roller t? will engage with the straight surface of the slot; l t. It will be seen, however, that when the rod 43 is swung downwardly upon its point of pivotal support and the walls of the recess 45 caused to embrace the roller t7, the rod 43 will serve to lock the mold assembly in the position shown in Figure l of the drawings. Of course. before this locking operation is effected, it is necess: ry to disengage the walls of the recess 35 of the rod filtl from the pin 3a, thereby disengaging the eccentric 38 from the mold assembly and permitting the same to remain in locked position as above described.

Referring now to the mechanism utilized for performing the last above described operations, the reference numeral denotes a shaft journaled in a laterally extending boss 51 formed upon the standard 1, said shaftbeing provided with a forwardly extending operating handle 52. Mounted upon the shaft 50 is an arm 53 provided with a roller 54, and also mounted upon said shaft and extending in an opposite direction with respect to the arm 53 is an arm 55 provided with a roller 56. The roller is disposed directly beneath the rod 36 and the roller 56 is disposed directly above the rod 43, so that when the shaft 50 is moved in a contra clockwise direction as by means of a downward thrust of the operating handle 52, the engagement of the roller 54 with the rod 36 will swing the latter upwardly to the position shown in Figure 2 while the engagement of the roller 56 with the rod 43 will swing the rod 43 downwardly to the position also shown in Figure 2; so that the rocking mechanism will be disengaged from the mold assembly and the latter locked in the position shown in Figure 2 by the engagement of the roller 47 with the walls of the recess 45. It is intended that this locking operation shall be effected at the termination of each vulcanizing operation whereupon it is necessary to shut off the supply of steam to the interior of the vulcanized tube. This operation is effected by means of an arm 57 mounted upon the shaft 50, said arm being connected by means of a link 58 with an arm 59 mounted upon the stem 60 of the threeway valve 26. It will be seen, therefore, that the downward thrust of the lever 52 will move the valve member 61 of the threeway valve 26 from the position shown in Figure 4 of the drawing to the position shown in Figure 5 of the drawing.

It is intended that the valve member 31 shall normally occupy the position shown in Figure 1, the valve being open to the source of suction and shut off from the air pressure, so that when the valve member 61 is moved to the position shown in Figure 5, the interior of the vulcanizing tube will be connected with the source of suction, whereby the steam present in the vulcanized tube will be quickly withdrawn therefrom. The valve member 31 may be operated manually as by means of a handle 62, so that when an un vulcanized tube is inserted in. the mold, the valve member 31 may be moved, so as to connect the interior of the tube through said valve and the three-way valve 26 with air from the pipe'32, whereby the same may be expanded within the mold. It will also be seen that if a vibratory movementbe given the operating handle (2 the interior of the vulcanized tube may be alternately connected and disconnected with and from the source of vacuum and air pressure, which operation assists in separating the surface of the vulcanized tube from the vulcanizing surface of the mold. The use-of the source of suction, however, is principally to withdraw the steam from the vulcanized tube, collapse it within the mold and withdraw therefrom any water oi. condensation that may he present therein subsequent to the vulcanizing operation.

In the en'il'iodiment oi my invention above described, it will be seen that during the rotativc n'n'n'emcnt ol the shaft 39, the mold assembly will he rocked continuously at a uniform speed. I have found in practice, however, that it is desirable to hold the mold assembly stationary when rocked to its rearmost position, to permit water ot condensation which may collect in the heating chamhers is and 17 of the mold sections 6 and 7 respectively. to be discharged from said cluimliicrs It will be con that the exhaust pipes 19 and 21, are disposed at the rearmost portions of their respective mold sections, it being intended to rock the mold through an angle of approximately 30, whereby when the mold assembly is tilted to its rearmost position; water of condensation will flow out by gravity through the discharge pipes 19 and 21.

Referring now to the embodiment of the invention shown in Figures 6 and 7 of the drawings,instead of providing an eccentric upon the drive shaft 39, I provide a wheel 63 provided withthe cam slot 64 which is adapted to receive a roller 65 journaled upon a lever 66 pivotally mounted at 67 upon the bracket 68. The outer end of the lever 66 has pivoted thereto at 69, the rod 70, which rod corresponds to the rod 36 in the first described embodiment; The rod 70 is pro vided with the recess l'l'which engages with a roller 72 provided upon a pin 73 mounted upon an arm 7st extending inwardly from the lower mold SGCt-lOHG. The cam slot 64; is provided with a dwell 75 which is so corelatcd with the other parts of the mechanism that when the shaft 39, through the cam mechanism, has rocked the mold assembly, the latter will beheld stationary for an intervalv of time in such a position as to permit the water of condensation to be discharged from the heating chambers oi": the mold sections through the discharge pipes.

Mounted upon a circular boss 76 provided upon the standard 1, a hell crank lever 77, having the arms 78, 79 and 80. The arm 78 is pivotally connected with a link 82 which in turn is pivotally connected at 83 with.

the rod 70. The shaft 50 is provided with a cam 84 which is adapted to engage with rollers 85 and '86 respectively journaled upon the outer ends of the arms 79 and 80 Mounted upon the shaft 50 is the arm 87 provided with a roller 88 adapted, when said arm 87 is swung downwardly, to engage vention.

with the locking rod 43 which is constructed in a manner identical with that shown in the first described embodiment of the in It will be seen, therefore, that when the handle 5:2 is moved downwardly, the cam 84 will swing the bell crank lever in a contraclockwise direction, disengage the operating rod 70 from the mold assembly and operatively connect the locking rod 43 with the recess e5.

It will be seen. that in this embodiment of my invention, the mold assembly is normally preferably slightly inclined toward the operator when the mold is in locked position. This facilitates the removal of the vulcanized tube from the lower section of the moldwhen the upper section is swung upwardly and it also facilitates the insertion of an unvulcanized tube in the lower section of the mold, preparatory to beginningauother vulcanizing operation.

referring now to Figures 1 and 6 of the drawing, the reference numeral 89 desig nates a fitting which is included in the flexible conduit 27 adjacent the valve stem 25 of the tube being vulcanized. This fitting is provided with an exhaust valve 90 adapted to be operated as by means of the handle .91. This exhaust valve, which is intended to be closed during the vulcanizing operation, is adapted, when opened, to discharge into the atmosphere steam or vapors generated in the article being vulcanized from water of condensation at the termination of the vulcanizing operation, as will hereinafter be described Having thus described preferred embodiments of mechanism adapted to carry out the various steps of my improved method, which steps have been largely set forth in the description of the mechanism preferably employed for carrying out said method, it will be seen that when the mold assembly is operatively connected with its rocking mechanism, the valve stem 25 of the tube being vulcanized is also operatively connected with the source of live steam, which steam is introduced into the interior of the tube through the flexible conduit 27 and the valve stem 25. Should water of condensation term in the tube being vulcanized, the constant rocking of the mold assembly will cause said water of condensation to move from place to place within the interior of the tube, whereby it will not be allowed to collect in any regional location therein, the result being that a uniform vulcanization of the tube wall will. be accomplished. water of condensation will also be prevented from collecting in any part of the steam chambers and thus hindering vulcanization at such point.

The operation of disconnecting the mold assembly from its rocking mechanism also shuts ed the supply of steam to the vulcanlltl ized tube and automatically connects the latter with the source of suction, whereby the said vulcanized tube will be quickly discharged of its steam and its water of condcnsation.

In many instances, I have found in practice that it is not necessary to completely collapse the tube within the mold, so as to remove therefrom the water of condensation, but to subject the vulcanized tube only to such degree of suction or sub-atmospheric pressure as will quickly remove the utilized steam vulcanizing medium from the tube, and perhaps loosen the tube from the walls of the mold. sections. For instance, should an extreme degree of suction or sub-atmospheric pressure be applied to the vulcanized tube, a portion thereof might be forced against the inner end of the valve stem with such pressure as would cause it to seal or close the passageway through the valve stem, thereby preventing the water of condensation from being discharged from said vulcanized tube, so that when the mold sections are opened, a quantity of water would still remain in the tube, which water, owing to its being heated to a much higher temperature than the boiling point of water at atmospheric pressure, would quickly generate such steam pressure within said vulcanized tube as might expand the latter to its bursting point, thereby destroying the tube.

I have found, therefore, that the exhaust valve 90 in the flexible conduit 27 may be utilized to perform an important step of my method. Inasmuch as the opening of this exhaust valve, when the steam utilized in the vulcanizing operation has been quickly removed by the application of vacuum or sub-atmospheric pressure, will permit the steam subsequently generated from the water of coi'ulensation remaining in the tube to be discharged to the atmosphere, and inasmuch as the mold remains in its heated condition, its generation of st ram from said water of condensation can be continued to such a time as will completely free the interior of the tube from any water of condensation, whether or not the tube has been collapsed within the mold by the application of suction. The operator will, therefore, quickly open this valve immediately subse quent to the withdrawal of the utilized vulcanizing medium from the tube subsequent to the termination of the vulcanizing operation. lVhen the flow of steam has substantially ceased through the exhaust valve 90, the operator will quickly open the mold and remove the vulcanized tube.

I have found that any slight moisture then remaining in the tube from the condensation of such steam as may still remain in the tube after the discharge of the water of condensation, is beneficial to the use of the tube in service.

In the above described preferred type of mechanism employed to carry out the various steps of my method, many of the operations are automatic or semi-automatic, and while I prefer to utilize such a mechanism to carry out the steps of themethod, it will be understood, of course, that all of these operations may be performed manually and that other changes which would result in a more complete automatic performance of the method might be added, or a diilerent combination of manual and automatic opera tions be provided without departing from the scope or spirit of the invention.

As pointed out above, this invention is applicable to hollow articles other than inner tubes, such, for instance, as tire casings, by suitably changing the cross sectional shape of the interior, of the mold members. The opening along the inner periphery of the casing could be sealed, if desired, as pointed out in my Patent 1,582,255 dated April 27, 1926. Accordingly, when I use the word tube in the claims, I do not intend to limit the same to an inner tube, but to also include other endless tubular articles such as tire casings.

\Vhen, in the claims, I refer to steam, I intend also to include any gas suitable for the purpose which is liable to condense so as to leave a condensate in a manner analogous to that in which steam condenses into water.

It will also be understood that various changes may be resorted to in the form, construction and arrangement of the several parts of the apparatus and in the steps followed, without departing from the spirit and scope of my invention; and hence I do not intend to be limited to the details herein shown and described except as they may be included in the claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A method of vulcanizing endless tubes which includes, injecting steam into the tube for vulcanization purposes, and swinging the tube during vulcanization so as to dislodge any deposit or deposits of water of condensation within the tube.

2. A method of vulcanizing endless tubes which includes, injecting steam into the tube for vulcanization purposes, and oscillating the tube during vulcanization so as to dislodge any deposit or deposits of waterof condensation within the tube.

3. A, method of vulcanizing endless tubes which includes, providing a tube mold, inserting an endless tube into the mold, injecting steam in the tube while in the mold for vulcanization purposes, and oscillating the mold during vulcanization so as to dislodge any deposit or deposits of water of condensation within the tube.

4. A, method of 'vuleanizing endless tubes which includes, providing a jacketed tube mold, inserting an endless tube into the mold, injecting steam into the tube while in the mold for vulcanization purposes, supplying steam to the j ecket, and, swinging the mold during vulcanization so as to dislodge any deposit or deposits of Water of condensation Within the tube and acket.

5. A method of vulcanizing endless tubes which includes, providing a, jacketed tube ever-25s inold inserting an endless tube into the mold, injecting steam into the tube While in the mold for vulcanization purposes, supplying steam to the jacket. and oscillating the mold duringvulcanization so as to dislodge any deposit or deposits of Water of condensation Within the tube and jacket.

t In testimony whereof, ll attix my signs-- ui'e.

WALTER L. FAIRCHELD. 

